We demonstrate a highly efficient hybrid crystalline silicon (c-Si) based photovoltaic devices with hole-transporting transparent conductive poly-(3,4-ethlenedioxythiophene):poly(styrenesufonic acid) (PEDOT:PSS) films, incorporating a Zonyl fluorosurfactant as an additive, compared to non additive devices. The usage of a 0.1% Zonly treated PEDOT:PSS improved the adhesion of precursor solution on hydrophobic c-Si wafer without any oxidation process. The average power conversion efficiency η value was 10.8%-11.3%, which was superior to those of non-treated devices. Consequently, c-Si/Zonyl-treated PEDOT:PSS heterojunction devices exhibited the highest η of 11.34%. The Zonyl-treated soluble PEDOT:PSS composite is promising as a hole-transporting transparent conducting layer for c-Si/organic photovoltaic applications.

p‐Toluenesulfonic acid/dimethyl sulfoxide (PTSA/DMSO)‐treated poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/crystalline‐silicon (c‐Si) hybrid solar cells with a solution‐processed anti‐reflection coating of TiO2 exhibit a record power conversion efficiency of 15.5%. Additionally, the performance stability of the hybrid device for both air storage and light exposure is improved due to removal of the PSS matrix from the PTSA/DMSO‐treated PEDOT:PSS thin film.

We demonstrate the chemistry of amphiphilic perfluorosulfonic copolymer Nafion-coated conductive poly(3,4-ethyelenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and its effect on the photovoltaic performance of PEDOT:PSS/crystalline Si (c-Si) heterojunction solar cells. The highly hydrophilic sulfonate group of insulating, chemically stable Nafion interacts with PSS in PEDOT:PSS, which reduce the Coulombic interaction between PEDOT and PSS. The highly hydrophobic fluorocarbon backbone of Nafion favorably interacts with hydrophobic PEDOT of PEDOT:PSS. These factors give rise to the extension of π-conjugation of PEDOT chains. Silver paste used as a top grid electrode diffused into the Nafion layer and contacted with underneath Nafion-modified PEDOT:PSS layer. As a consequent, solution-processed Nafion-coated PEDOT:PSS/c-Si heterojunction solar cells exhibited a higher power conversion efficiency of 14.0% with better stability for light soaking rather than that of the pristine PEDOT:PSS/c-Si device by adjusting the layer thickness of Nafion. These findings originate from the chemical stability of hydrophobic fluorocarbon backbone of Nafion, diffusivity of silver paste into Nafion and contact with PEDOT:PSS, and Nafion as an antireflection layer.

We explored thiocyanate (SCN)-based two-dimensional (2D) organometal lead halide perovskite families toward photovoltaic applications. Using an SCN axial ligand and various cation species, we examined AA′PbI 2 (SCN) 2 -type 2D perovskite by replacing the cation species (AA′) between methylammonium (MA), formamidinium (FA), and cesium. Among various cation compositions, only all-inorganic cesium-based SCN perovskite, Cs 2 PbI 2 (SCN) 2 , film showed high thermal stability compared to known 2D perovskites. Perovskite solar cells (PSCs) using the Cs 2 PbI 2 (SCN) 2 absorber yielded approximately 2% conversion efficiency on the mesoscopic device. Relatively low efficiency is attributed, in addition to optical properties (large band gap (2.05 eV) and exciton absorption), to the orientation of perovskite layer parallel to the layered structure, preventing carrier extraction from the light-absorber perovskite. In device stability, the Cs-based 2D perovskite was stable against oxygen (oxidation), whereas it was found to be unstable against humidity. X-ray diffraction and X-ray photoelectron spectroscopy measurements showed that, unlike long alkylammonium-based 2D perovskite families such as BA 2 PbI 4 (BA = butylammonium), the Cs-based 2D perovskite can undergo hydrolysis due to the hydrophilic Cs cations.

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